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Biomedical subjects

N W Goodman

Publications and source records attributed to N W Goodman.

At least 109 records · Page 6Linked to original sources
PubMed1990

Gastro-oesophageal reflux during elective laparoscopy.

An oesophageal pH electrode was used to record gastro-oesophageal reflux in 73 women who had elective laparoscopy for various gynaecological procedures. No refluxes were recorded during the 63 procedures from which results could be analysed; the upper 95% confidence limit from this observation is 3 in 63 (4.8%). Two of the excluded women refluxed during episodes of hiccough that occurred shortly after induction of anaesthesia. Tracheal intubation may be required during laparoscopy, although the need to protect against the possibility of aspiration of gastric contents may not be a valid reason unless, with the same logic, it is suggested that all patients who hiccough should be intubated.

Adolescent↗
PubMed1989

Effects of incremental doses of alfentanil and propofol on the breathing of anaesthetized patients.

Incremental doses of alfentanil and propofol were given to anaesthetized healthy patients undergoing routine orthopaedic surgery. Ventilation was recorded by respiratory inductance plethysmography and analysed by microcomputer. Alfentanil affected primarily expiratory time. The onset of effect lasted 82 s (range 25-173 s); offset was exponential, with a half-life of 146 s (range 62-260 s). Alfentanil also reduced tidal volume, but the effect was less obvious and less consistent. Propofol affected primarily tidal volume. The onset of effect lasted 34 s (range 17-69 s); offset was linear, with a time to 50% recovery of 92 s (range 47-161 s). Propofol had little effect on expiratory time. The drugs had little effect on inspiratory time. Three patients showed periods when the distribution of expiratory times was bimodal; the mechanism for this is unknown.

Adult↗
PubMed1989

Gastro-oesophageal reflux in pregnancy at term and after delivery.

Gastro-oesophageal reflux during a 40-minute reflux provocation test was assessed by lower oesophageal pH monitoring in 25 pregnant women at term, and again on about the second day after delivery. At term 17 women refluxed a total of 29 times; after delivery five women refluxed once each. There was a significant decrease in gastro-oesophageal reflux by the second day after delivery (p less than 0.05). Gastro-oesophageal reflux is, however, only one of the factors that predisposes to acid aspiration pneumonitis.

Esophagus↗
PubMed1987

Some ventilatory effects of propofol as sole anaesthetic agent.

Ventilatory effects of propofol, used as a sole agent for the induction and maintenance of general anaesthesia, were studied in 14 healthy unpremedicated patients. Subarachnoid anaesthesia was established before induction of general anaesthesia. Induction was with propofol 2.5 mg kg-1 given while the patients breathed 100% oxygen. We intended to start an infusion of propofol 100 micrograms kg-1 min-1; maintain it for at least 25 min; make a first set of quasi-steady-state observations; double the infusion; and repeat observations after 25 min. The single induction bolus plus single rate infusion was not totally satisfactory: further boluses were usually needed. At induction there was apnoea in all but three patients, sometimes lasting more than 3 min; hyperventilation before induction, combined with hyperoxia, probably exaggerated this. Established ventilatory rates were generally 30% higher than awake. One patient became bradypnoeic. Tidal volume and minute ventilation, and the Tl:Ttot ratio, were reduced. Doubling the infusion rate had no clear effect on frequency or tidal volume, but it further reduced the Tl:Ttot ratio and caused an increase in PE'CO2 of 1 kPa. The ventilatory response to carbon dioxide was 58% of baseline awake control (95% confidence limits +/- 26%) at the lower infusion rate, with further slight depression when the infusion rate was doubled. Doubling the rate of infusion of propofol did not give twice the effect on ventilation, and probably is not giving twice the "depth" of anaesthesia. We cannot say if this is for pharmacokinetic or pharmacodynamic reasons.

Adult↗
PubMed1987

Inter-relations of the volume and timing components of ventilation during carbon dioxide rebreathing in awake and anaesthetized subjects.

We studied the relations between the volume and timing components of ventilation during carbon dioxide rebreathing in conscious subjects and patients anaesthetized with propofol. In conscious responses, breath-by-breath minute ventilation (VI) generally correlated better with end-tidal carbon dioxide than did tidal volume (VT), but VT correlated better than VI in the anaesthetized responses. The source of this difference was that, whereas VT and the inspiratory period were both smaller and less variable when subjects were anaesthetized rather than conscious, the expiratory period was no less variable, and this disturbed the usual inverse relation between VT and the duration of the ventilatory cycle. Anaesthesia stabilized the switch from inspiration to expiration, but not that from expiration to inspiration. In some patients, it produced a disturbance pronounced enough to suggest bimodality of the timing of expiration.

Adult↗
PubMed1987

Massive intraoperative pulmonary embolism in a child.

An 11-yr-old girl suffered a massive pulmonary embolus during an operation to insert an artificial bladder sphincter. Forty minutes after the induction of anaesthesia, the heart rate increased and she became hypotensive and deeply cyanosed. A definitive diagnosis was not made during surgery, but she improved after 45 min of resuscitation with 100% oxygen, infusion of normal saline, ephedrine (total 45 mg) and intermittent external cardiac massage. The diagnosis was proved the next day by lung perfusion scan. There were no apparent risk factors.

Child↗
PubMed1985

The ventilatory response to carbon dioxide. An analysis of data obtained by the rebreathing method.

The ventilatory response to carbon dioxide using the rebreathing method was studied repeatedly in four healthy volunteers. The data were collected and processed in different ways using a microcomputer. Least squares linear regression analysis described the responses almost as accurately as a non-linear second-order polynomial regression. Linear regression analysis was undertaken on VI/PE'CO2 points, first breath-by-breath and then on three different groupings of breaths. The gradients and intercepts obtained by grouping agreed with those from breath-by-breath analysis both for a single response and for the mean result of a number of responses. Grouping tended to increase the correlation coefficient of a response, but widened the statistical confidence limits of the calculated gradient. The performance variability between repeated responses, the same no matter which data points were used, produced a range of gradients for each subject which was larger than the confidence limits on the gradient of a single response.

Adult↗
PubMed1985

Analyses of the ventilatory response to carbon dioxide. Implications for clinical research.

Baseline control estimations of the ventilatory response to carbon dioxide by the rebreathing method were attempted in 92 patients. When analysed retrospectively, only 53 were both technically and statistically satisfactory, although even these gave rise to some doubts. As the breath-by-breath correlation between ventilation (VI) and end-tidal carbon dioxide (PE'CO2) decreased there was a tendency for the gradients to become suspiciously low and for estimates in an individual gradient to become sensitive to the method of analysis. Even so, when responses were grouped according to correlation, the method of analysis did not alter the mean gradient within a group. Single estimates of the carbon dioxide response at each stage of a study may not be a very powerful technique in clinical research; multiple estimates, if they can be arranged, would be more satisfactory.

Carbon Dioxide↗